1. Field of the Invention
The present invention relates to a motorcycle tire having an improved turning performance without deteriorating other performance.
2. Description of the Related Art
Referring to FIG. 5, a typical motorcycle has a steerable front wheel (af) and a rear wheel (ar). In order for the motorcycle to turn, the motorcycle is banked toward the desired left or right turning direction with respect to a roll axis z while giving the front wheel (af) a small steering angle according to the degree of the bank. In a certain moment of the turning, the typical roll axis z is an axis that extends from a ground contact point (pr) of the rear wheel (ar) toward the upward and the forward direction.
In order to improve the turning performance of the motorcycle, the motorcycle tire is requested to be easily banked by a driver during the beginning of the turning. On the other hand, when the final stage of turning that the motorcycle is banked at about the maximum bank angle, it is also requested that the tire generates a resistance force for preventing a further banked and holding the full banked state. Namely, the motorcycle tire is requested to have a property including easy rolled or banked performance at the beginning of turning and resistance performance for preventing further roll at the full banked state.
Referring to FIG. 6, JP-2009-298387A1 discloses a motorcycle tire having a tread portion including: a center region (a) which comes into contact with the ground when the tire travels in straight; and a pair of shoulder regions (b) which come into contact with the ground during turning. The center region (a) is provided with a circumferentially extending center main groove g1 on the tire equator C, and a pair of circumferentially extending middle grooves g2 provided axially both sides of the center main groove g1, and is not provided with any inclined grooves.
However, the tire described above has unsatisfactory turning performance.